Greece’s government on Monday said it is preparing a rent-assistance program to help the growing number of migrants in the country who are faced with the oncoming winter and mounting resistance against their arrival elsewhere in Europe.

At the end of a contentious summit, European and Balkan leaders committed early Monday to add capacity for receiving about 100,000 more migrants to help ease the plight of the tens of thousands coming from Syria and beyond and moving across the Balkans toward the European Union’s heartland.

With freezing weather setting in, tens of thousands of migrants surging across Europe could face even more hurdles after European Union leaders pledged to stem their flow by introducing tighter border controls.

A day before a European summit on the migrant crisis, Slovenia’s president demanded immediate action from the EU and tempers flared at one overcrowded refugee center as thousands more asylum-seekers poured into the tiny Alpine nation.